Some biological components, including multi-component materials such as fibrin and its base components (fibrinogen and thrombin), are delicate materials and cannot tolerate processing with conventional sterilization techniques without being significantly compromised or even destroyed when they are in solution. Traditionally, such biological components are manufactured in two packages, the first including a terminally sterilized delivery device, and the second being an aseptically filled vial with non-sterile exterior. While this allows for control of the products, unfortunately the biological materials must then be transferred into the applicator at the time of use. This multi-step process requires some unusual coordination between sterile and nonsterile surgical staff, and may lead to errors or anxiety on the part of that staff. Further, the transfer of materials into a delivery device itself lends itself to potential mistakes and leakage/spillage of material. It would be more desirable for users if the biological products can be delivered in a pre-loaded and sterilized applicator, such that the entire contents could be deposited on the sterile field without the need for further preparation steps.
It is one objective of the present invention to provide a product with this capability to deliver materials pre-loaded and ready for dispensing without filling or loading materials into an applicator. Some two-part materials, such as fibrin sealants, are highly reactive with one another, and it is critical that even the slightest amount of cross-contamination between first and second materials be prevented. Cross-contamination would not only render the device useless, but would require a costly decontamination of the assembly area. To protect against such cross-contamination, it may be desired that each reactive material be loaded and sealed in a separate vessel, and then brought together into a unified device at the time of use without having to transfer the fluid materials into a separate vial or barrel. It is a further objective of the invention to provide for a means of assembly that minimizes potential for cross-contamination.
Further, it is important that the components of the delivery assembly be sterile inside and outside. Even with pre-sterilization of all components entering a filling region, the ability to claim sterility on the exterior of product has traditionally been questionable. It is therefore helpful and is one additional objective of the invention to subject the entire exterior of the device to low level of radiation energy, such as with an electron-beam, after filling with biological or reactive components. This poses a number of unique design challenges, since the exterior surfaces of the device that can be touched by the user, or that come into contact with fluids inadvertently leaked or spilled on the device must be “visible” to the electron beam, since the beam is propagated in a purely linear manner from its source. When such sterilization techniques are used, it is particularly helpful that there be no shadowing, cracks, steps, or crevasses on the device that block line of sight of the beam to these surfaces.